What does empty mean? What does isset mean? What does !empty mean and what does !isset mean? With Google, I did not find anything sensible.

PS And about the exclamation marks found nothing.

    2 answers 2

    isset - whether a variable exists.

    empty - whether the variable is empty.

    Well, with the sign "!" all the way around :)

    • And add for fans to save on matches: isset is faster. - ling

    Empty() determines whether the variable is set: a description .

    Isset() also determines whether a variable is set: a description .

    They have differences, read the links.

    "!" denial means, for example:

     <?php $a = null; if (!isset($a)) Echo "Переменная не установленна"; ?>